[linux-2.6-block.git] / drivers / i2c / muxes / i2c-demux-pinctrl.c

/*
 * Pinctrl based I2C DeMultiplexer
 *
 * Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
 * Copyright (C) 2015-16 by Renesas Electronics Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; version 2 of the License.
 *
 * See the bindings doc for DTS setup and the sysfs doc for usage information.
 * (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
 */

#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/sysfs.h>

struct i2c_demux_pinctrl_chan {
	struct device_node *parent_np;
	struct i2c_adapter *parent_adap;
	struct of_changeset chgset;
};

struct i2c_demux_pinctrl_priv {
	int cur_chan;
	int num_chan;
	struct device *dev;
	const char *bus_name;
	struct i2c_adapter cur_adap;
	struct i2c_algorithm algo;
	struct i2c_demux_pinctrl_chan chan[];
};

static struct property status_okay = { .name = "status", .length = 3, .value = "ok" };

static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;

	return __i2c_transfer(parent, msgs, num);
}

static u32 i2c_demux_functionality(struct i2c_adapter *adap)
{
	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;

	return parent->algo->functionality(parent);
}

static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
{
	struct i2c_adapter *adap;
	struct pinctrl *p;
	int ret;

	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
	if (ret)
		goto err;

	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
	if (!adap) {
		ret = -ENODEV;
		goto err;
	}

	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
	if (IS_ERR(p)) {
		ret = PTR_ERR(p);
		goto err_with_put;
	}

	priv->chan[new_chan].parent_adap = adap;
	priv->cur_chan = new_chan;

	/* Now fill out current adapter structure. cur_chan must be up to date */
	priv->algo.master_xfer = i2c_demux_master_xfer;
	priv->algo.functionality = i2c_demux_functionality;

	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
		 "i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
	priv->cur_adap.owner = THIS_MODULE;
	priv->cur_adap.algo = &priv->algo;
	priv->cur_adap.algo_data = priv;
	priv->cur_adap.dev.parent = priv->dev;
	priv->cur_adap.class = adap->class;
	priv->cur_adap.retries = adap->retries;
	priv->cur_adap.timeout = adap->timeout;
	priv->cur_adap.quirks = adap->quirks;
	priv->cur_adap.dev.of_node = priv->dev->of_node;
	ret = i2c_add_adapter(&priv->cur_adap);
	if (ret < 0)
		goto err_with_put;

	return 0;

 err_with_put:
	i2c_put_adapter(adap);
 err:
	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
	return ret;
}

static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
{
	int ret, cur = priv->cur_chan;

	if (cur < 0)
		return 0;

	i2c_del_adapter(&priv->cur_adap);
	i2c_put_adapter(priv->chan[cur].parent_adap);

	ret = of_changeset_revert(&priv->chan[cur].chgset);

	priv->chan[cur].parent_adap = NULL;
	priv->cur_chan = -EINVAL;

	return ret;
}

static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
{
	int ret;

	if (new_chan == priv->cur_chan)
		return 0;

	ret = i2c_demux_deactivate_master(priv);
	if (ret)
		return ret;

	return i2c_demux_activate_master(priv, new_chan);
}

static ssize_t available_masters_show(struct device *dev,
				      struct device_attribute *attr,
				      char *buf)
{
	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	int count = 0, i;

	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
		count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%s%c",
				   i, priv->chan[i].parent_np->full_name,
				   i == priv->num_chan - 1 ? '\n' : ' ');

	return count;
}
static DEVICE_ATTR_RO(available_masters);

static ssize_t current_master_show(struct device *dev,
				   struct device_attribute *attr,
				   char *buf)
{
	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", priv->cur_chan);
}

static ssize_t current_master_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{
	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	unsigned int val;
	int ret;

	ret = kstrtouint(buf, 0, &val);
	if (ret < 0)
		return ret;

	if (val >= priv->num_chan)
		return -EINVAL;

	ret = i2c_demux_change_master(priv, val);

	return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(current_master);

static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct i2c_demux_pinctrl_priv *priv;
	int num_chan, i, j, err;

	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
	if (num_chan < 2) {
		dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
		return -EINVAL;
	}

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
			   + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
	if (err)
		return err;

	for (i = 0; i < num_chan; i++) {
		struct device_node *adap_np;

		adap_np = of_parse_phandle(np, "i2c-parent", i);
		if (!adap_np) {
			dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
			err = -ENOENT;
			goto err_rollback;
		}
		priv->chan[i].parent_np = adap_np;

		of_changeset_init(&priv->chan[i].chgset);
		of_changeset_update_property(&priv->chan[i].chgset, adap_np, &status_okay);
	}

	priv->num_chan = num_chan;
	priv->dev = &pdev->dev;

	platform_set_drvdata(pdev, priv);

	/* switch to first parent as active master */
	i2c_demux_activate_master(priv, 0);

	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
	if (err)
		goto err_rollback;

	err = device_create_file(&pdev->dev, &dev_attr_current_master);
	if (err)
		goto err_rollback_available;

	return 0;

err_rollback_available:
	device_remove_file(&pdev->dev, &dev_attr_available_masters);
err_rollback:
	for (j = 0; j < i; j++) {
		of_node_put(priv->chan[j].parent_np);
		of_changeset_destroy(&priv->chan[j].chgset);
	}

	return err;
}

static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
{
	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
	int i;

	device_remove_file(&pdev->dev, &dev_attr_current_master);
	device_remove_file(&pdev->dev, &dev_attr_available_masters);

	i2c_demux_deactivate_master(priv);

	for (i = 0; i < priv->num_chan; i++) {
		of_node_put(priv->chan[i].parent_np);
		of_changeset_destroy(&priv->chan[i].chgset);
	}

	return 0;
}

static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
	{ .compatible = "i2c-demux-pinctrl", },
	{},
};
MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);

static struct platform_driver i2c_demux_pinctrl_driver = {
	.driver	= {
		.name = "i2c-demux-pinctrl",
		.of_match_table = i2c_demux_pinctrl_of_match,
	},
	.probe	= i2c_demux_pinctrl_probe,
	.remove	= i2c_demux_pinctrl_remove,
};
module_platform_driver(i2c_demux_pinctrl_driver);

MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-demux-pinctrl");
Commit	Line	Data
50a5ba87 WS	1	/*
	2	* Pinctrl based I2C DeMultiplexer
	3	*
	4	* Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
	5	* Copyright (C) 2015-16 by Renesas Electronics Corporation
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the
	9	* Free Software Foundation; version 2 of the License.
	10	*
	11	* See the bindings doc for DTS setup and the sysfs doc for usage information.
	12	* (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
	13	*/
	14
	15	#include <linux/i2c.h>
	16	#include <linux/init.h>
	17	#include <linux/module.h>
	18	#include <linux/of.h>
	19	#include <linux/pinctrl/consumer.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/slab.h>
	22	#include <linux/sysfs.h>
	23
	24	struct i2c_demux_pinctrl_chan {
	25	struct device_node *parent_np;
	26	struct i2c_adapter *parent_adap;
	27	struct of_changeset chgset;
	28	};
	29
	30	struct i2c_demux_pinctrl_priv {
	31	int cur_chan;
	32	int num_chan;
	33	struct device *dev;
	34	const char *bus_name;
	35	struct i2c_adapter cur_adap;
	36	struct i2c_algorithm algo;
	37	struct i2c_demux_pinctrl_chan chan[];
	38	};
	39
	40	static struct property status_okay = { .name = "status", .length = 3, .value = "ok" };
	41
	42	static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
	43	{
	44	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	45	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	46
	47	return __i2c_transfer(parent, msgs, num);
	48	}
	49
	50	static u32 i2c_demux_functionality(struct i2c_adapter *adap)
	51	{
	52	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	53	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	54
	55	return parent->algo->functionality(parent);
	56	}
	57
	58	static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	59	{
	60	struct i2c_adapter *adap;
	61	struct pinctrl *p;
	62	int ret;
	63
	64	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
65	if (ret)
66	goto err;
67
68	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
69	if (!adap) {
70	ret = -ENODEV;
71	goto err;
72	}
73
74	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
75	if (IS_ERR(p)) {
76	ret = PTR_ERR(p);
77	goto err_with_put;
78	}
79
80	priv->chan[new_chan].parent_adap = adap;
81	priv->cur_chan = new_chan;
82
83	/* Now fill out current adapter structure. cur_chan must be up to date */
84	priv->algo.master_xfer = i2c_demux_master_xfer;
85	priv->algo.functionality = i2c_demux_functionality;
86
87	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
88	"i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
89	priv->cur_adap.owner = THIS_MODULE;
90	priv->cur_adap.algo = &priv->algo;
91	priv->cur_adap.algo_data = priv;
92	priv->cur_adap.dev.parent = priv->dev;
93	priv->cur_adap.class = adap->class;
94	priv->cur_adap.retries = adap->retries;
95	priv->cur_adap.timeout = adap->timeout;
96	priv->cur_adap.quirks = adap->quirks;
97	priv->cur_adap.dev.of_node = priv->dev->of_node;
98	ret = i2c_add_adapter(&priv->cur_adap);
99	if (ret < 0)
100	goto err_with_put;
101
102	return 0;
103
104	err_with_put:
105	i2c_put_adapter(adap);
106	err:
107	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
108	return ret;
109	}
110
111	static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
112	{
113	int ret, cur = priv->cur_chan;
114
115	if (cur < 0)
116	return 0;
117
118	i2c_del_adapter(&priv->cur_adap);
119	i2c_put_adapter(priv->chan[cur].parent_adap);
120
121	ret = of_changeset_revert(&priv->chan[cur].chgset);
122
123	priv->chan[cur].parent_adap = NULL;
124	priv->cur_chan = -EINVAL;
125
126	return ret;
127	}
128
129	static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
130	{
131	int ret;
132
133	if (new_chan == priv->cur_chan)
134	return 0;
135
136	ret = i2c_demux_deactivate_master(priv);
137	if (ret)
138	return ret;
139
140	return i2c_demux_activate_master(priv, new_chan);
141	}
142
c0c508a4 BH	143	static ssize_t available_masters_show(struct device *dev,
	144	struct device_attribute *attr,
	145	char *buf)
50a5ba87 WS	146	{
	147	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	148	int count = 0, i;
	149
	150	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
c0c508a4 BH	151	count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%s%c",
	152	i, priv->chan[i].parent_np->full_name,
	153	i == priv->num_chan - 1 ? '\n' : ' ');
50a5ba87 WS	154
	155	return count;
	156	}
c0c508a4	157	static DEVICE_ATTR_RO(available_masters);
50a5ba87	158
c0c508a4 BH	159	static ssize_t current_master_show(struct device *dev,
	160	struct device_attribute *attr,
	161	char *buf)
	162	{
	163	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	164
	165	return sprintf(buf, "%d\n", priv->cur_chan);
	166	}
	167
	168	static ssize_t current_master_store(struct device *dev,
	169	struct device_attribute *attr,
	170	const char *buf, size_t count)
50a5ba87 WS	171	{
	172	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	173	unsigned int val;
	174	int ret;
	175
	176	ret = kstrtouint(buf, 0, &val);
	177	if (ret < 0)
	178	return ret;
	179
	180	if (val >= priv->num_chan)
	181	return -EINVAL;
	182
	183	ret = i2c_demux_change_master(priv, val);
	184
	185	return ret < 0 ? ret : count;
	186	}
c0c508a4	187	static DEVICE_ATTR_RW(current_master);
50a5ba87 WS	188
	189	static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
	190	{
	191	struct device_node *np = pdev->dev.of_node;
	192	struct i2c_demux_pinctrl_priv *priv;
	193	int num_chan, i, j, err;
	194
	195	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
	196	if (num_chan < 2) {
	197	dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
	198	return -EINVAL;
	199	}
	200
	201	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
	202	+ num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
	203	if (!priv)
	204	return -ENOMEM;
	205
	206	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
	207	if (err)
	208	return err;
	209
	210	for (i = 0; i < num_chan; i++) {
	211	struct device_node *adap_np;
	212
	213	adap_np = of_parse_phandle(np, "i2c-parent", i);
	214	if (!adap_np) {
	215	dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
	216	err = -ENOENT;
	217	goto err_rollback;
	218	}
	219	priv->chan[i].parent_np = adap_np;
	220
	221	of_changeset_init(&priv->chan[i].chgset);
	222	of_changeset_update_property(&priv->chan[i].chgset, adap_np, &status_okay);
	223	}
	224
	225	priv->num_chan = num_chan;
	226	priv->dev = &pdev->dev;
	227
	228	platform_set_drvdata(pdev, priv);
	229
	230	/* switch to first parent as active master */
	231	i2c_demux_activate_master(priv, 0);
	232
c0c508a4	233	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	234	if (err)
	235	goto err_rollback;
	236
c0c508a4 BH	237	err = device_create_file(&pdev->dev, &dev_attr_current_master);
	238	if (err)
	239	goto err_rollback_available;
	240
50a5ba87 WS	241	return 0;
50a5ba87 WS	242
c0c508a4 BH	243	err_rollback_available:
c0c508a4 BH	244	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	245	err_rollback:
	246	for (j = 0; j < i; j++) {
	247	of_node_put(priv->chan[j].parent_np);
	248	of_changeset_destroy(&priv->chan[j].chgset);
	249	}
	250
	251	return err;
	252	}
	253
	254	static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
	255	{
	256	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
	257	int i;
	258
c0c508a4 BH	259	device_remove_file(&pdev->dev, &dev_attr_current_master);
c0c508a4 BH	260	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	261
	262	i2c_demux_deactivate_master(priv);
	263
	264	for (i = 0; i < priv->num_chan; i++) {
	265	of_node_put(priv->chan[i].parent_np);
	266	of_changeset_destroy(&priv->chan[i].chgset);
	267	}
	268
	269	return 0;
	270	}
	271
	272	static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
	273	{ .compatible = "i2c-demux-pinctrl", },
	274	{},
	275	};
	276	MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
	277
	278	static struct platform_driver i2c_demux_pinctrl_driver = {
	279	.driver = {
	280	.name = "i2c-demux-pinctrl",
	281	.of_match_table = i2c_demux_pinctrl_of_match,
	282	},
	283	.probe = i2c_demux_pinctrl_probe,
	284	.remove = i2c_demux_pinctrl_remove,
	285	};
	286	module_platform_driver(i2c_demux_pinctrl_driver);
	287
	288	MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
	289	MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
	290	MODULE_LICENSE("GPL v2");
	291	MODULE_ALIAS("platform:i2c-demux-pinctrl");